Maternal, but not fetal, administration of corticosteroids restricts fetal growth

Respiratory benefit in preterm lambs is progressively lost when the concentration of fetal plasma betamethasone is titrated below two nanograms per milliliter

Antenatal steroid therapy is the standard of care for women at imminent risk of preterm delivery. Current dosing regimens use suprapharmacological doses to achieve extended fetal steroid exposures. We aimed to determine the lowest fetal plasma betamethasone concentration sufficient to achieve functional preterm lung maturation. Ewes with single fetuses underwent surgery to install a fetal jugular catheter. Adopting a stepwise design, ewes were randomized to either a saline-only group (negative control group; n = 9) or one of four betamethasone treatment groups. Each betamethasone group fetus received a fetal intravenous infusion to target a constant plasma betamethasone level of either 1) 2 ng/mL (2 ng/mL positive control group, n = 9); 2) 1 ng/mL, (1 ng/mL group, n = 10); 3) 0.5 ng/mL (0.5 ng/mL group, n = 10); or 4) 0.25 ng/mL (0.25 ng/mL group, n = 10). Fetuses were infused for 48 h, delivered, and ventilated. The positive control group, negative control group, and mid-point 0.5 ng/mL group animals were tested first. An interim analysis informed the final betamethasone group tested. Positive control group animals had large, statistically significant improvements in respiratory function. Based on an interim analysis, the 1.0 ng/mL group was studied in favor of the 0.25 ng/mL group. Treatment efficacy was progressively lost at plasma betamethasone concentrations lower than 2 ng/mL. We demonstrated that the acute respiratory benefit conveyed by antenatal steroid exposure in the fetal sheep is progressively lost when constant fetal plasma betamethasone concentrations are reduced below a targeted value of 2 ng/mL.NEW & NOTEWORTHY Lung maturation benefits in preterm lambs were progressively lost when fetal plasma betamethasone concentrations fell below 2 ng/mL. The effective floor threshold for a robust, lung-maturing exposure likely lies between 1 and 2 ng betamethasone per milliliter of plasma. Hypothalamic pituitary adrenal axis signaling and immunocyte populations remained materially disrupted at subtherapeutic steroid concentrations. These data demonstrate the potential to improve antenatal steroid therapy using reduced dose regimens informed by glucocorticoid pharmacokinetics and pharmacodynamics.

A framework for testing pathways from prenatal stress-responsive hormones to cardiovascular disease risk

Cardiovascular disease (CVD) is a leading cause of death globally, with the prevalence projected to keep rising. Risk factors for adult CVD emerge at least as early as the prenatal period. Alterations in stress-responsive hormones in the prenatal period are hypothesized to contribute to CVD in adulthood, but little is known about relations between prenatal stress-responsive hormones and early precursors of CVD, such as cardiometabolic risk and health behaviors. The current review presents a theoretical model of the relation between prenatal stress-responsive hormones and adult CVD through cardiometabolic risk markers (e.g., rapid catch-up growth, high BMI/adiposity, high blood pressure, and altered blood glucose, lipids, and metabolic hormones) and health behaviors (e.g., substance use, poor sleep, poor diet and eating behaviors, and low physical activity levels). Emerging evidence in human and non-human animal literatures suggest that altered stress-responsive hormones during gestation predict higher cardiometabolic risk and poorer health behaviors in offspring. This review additionally highlights limitations of the current literature (e.g., lack of racial/ethnic diversity, lack of examination of sex differences), and discusses future directions for this promising area of research.

Chronic maternal hypercortisolemia models stress-induced adverse birth outcome and altered cardiac function in newborn lambs

Maternal stress in pregnancy is thought to be a contributing factor in adverse pregnancy outcome, including stillbirth and prematurity. Previous studies in our laboratory have shown that chronic elevation in maternal cortisol concentration in ewes (by maternal infusion of 1 mg·kg^-1·day^-1) during the late gestion increased the incidence of stillbirth and altered fetal heart rate and blood pressure at birth. We designed the current study to test the effect of chronically elevated maternal cortisol on fetal cardiac adaption from in utero life to ex utero life. The combined risk of stillbirth or prematurity was significantly greater in the pregnancies with maternal hypercortisolemia: in this cohort, 40% of the lambs of cortisol-infused ewes died in utero or at birth compared to 25% of lambs of control ewes, and 24% of lambs of cortisol-infused ewes were born preterm, whereas no lamb was born preterm in the control group. Compared to control lambs, the lambs of cortisol-infused ewes born at full term exhibited a significant increase in mean aortic pressure just prior to birth, and a significant decrease in mean aortic pressure that was evident during the first 9 hours after birth. The QT interval was decreased prior to birth and increased immediately after birth in the newborns of cortisol-treated ewes compared to control lambs. These findings suggest that an excess in utero corticosteroid exposure adversely affects fetal cardiac adaptation to extrauterine life and that chronic maternal stress or hypersecretion of corticosteroids may contribute to adverse obstetric outcomes.

Glucocorticoid-Mediated Developmental Programming of Vertebrate Stress Responsivity

Glucocorticoids, vertebrate steroid hormones produced by cells of the adrenal cortex or interrenal tissue, function dynamically to maintain homeostasis under constantly changing and occasionally stressful environmental conditions. They do so by binding and thereby activating nuclear receptor transcription factors, the Glucocorticoid and Mineralocorticoid Receptors (MR and GR, respectively). The GR, by virtue of its lower affinity for endogenous glucocorticoids (cortisol or corticosterone), is primarily responsible for transducing the dynamic signals conveyed by circadian and ultradian glucocorticoid oscillations as well as transient pulses produced in response to acute stress. These dynamics are important determinants of stress responsivity, and at the systemic level are produced by feedforward and feedback signaling along the hypothalamus-pituitary-adrenal/interrenal axis. Within receiving cells, GR signaling dynamics are controlled by the GR target gene and negative feedback regulator fkpb5. Chronic stress can alter signaling dynamics via imperfect physiological adaptation that changes systemic and/or cellular set points, resulting in chronically elevated cortisol levels and increased allostatic load, which undermines health and promotes development of disease. When this occurs during early development it can "program" the responsivity of the stress system, with persistent effects on allostatic load and disease susceptibility. An important question concerns the glucocorticoid-responsive gene regulatory network that contributes to such programming. Recent studies show that klf9, a ubiquitously expressed GR target gene that encodes a Krüppel-like transcription factor important for metabolic plasticity and neuronal differentiation, is a feedforward regulator of GR signaling impacting cellular glucocorticoid responsivity, suggesting that it may be a critical node in that regulatory network.

Effect of maternal betamethasone administration on feto-placental vascular resistance in the mouse†

Antenatal corticosteroids are often administered to women at risk of preterm birth to accelerate fetal lung development; however, there is evidence that this treatment may adversely affect placental function in some fetuses. Our group has recently demonstrated that wave reflections in the umbilical artery (UA), measured using high-frequency ultrasound, are sensitive to placental vascular abnormalities. In the present study, we used this approach to investigate the effect of maternal administration of betamethasone, a clinically relevant corticosteroid, on the feto-placental vasculature of the mouse. Fetuses were assessed at embryonic day (E)15.5 and E17.5 in C57BL6/J mice. At both gestational ages, the UA diameter, UA blood flow, and the wave reflection coefficient were significantly elevated in the betamethasone-treated mice compared to vehicle-treated controls. These observations support the interpretation that placental vascular resistance dropped with betamethasone treatment to an extent that could not be explained by vasodilation of the UA alone. Consistent with clinical studies, the effect of betamethasone on UA end-diastolic velocity was heterogeneous. Our results suggest that UA wave reflections are more sensitive to acute changes in placental vascular resistance compared with the UA pulsatility index, and this technique may have clinical application to identify a favorable placental vascular response to fetal therapies such as antenatal corticosteroids, where the fetal heart rate is likely to vary.

The reproductive stress hypothesis

In this paper, we propose the reproductive stress hypothesis that describes the pregnant females response to reproductive events based upon the activation of the hypothalamic–pituitary–adrenal axis and sympathetic adrenomedullary system. The main components of the reproductive stress hypothesis can be summarized as follows: (1) events unique to reproduction including empathema, pregnancy, parturition and lactation cause non-specific responses in females, called active reproductive stress; (2) the fetus is a special stressor for pregnant females where endocrine hormones, including corticotropin-releasing hormones and fetal glucocorticoids secreted by the fetus and placenta, enter the maternal circulatory system, leading to another stress response referred to as passive reproductive stress and (3) response to uterine tension and intrauterine infection is the third type of stress, called fetal intrauterine stress. Appropriate reproductive stress is a crucial prerequisite in normal reproductive processes. By contrast, excessive or inappropriate reproductive stress may result in dysfunctions of the reproductive system, such as compromised immune function, leading to susceptibility to disease. The novel insights of the reproductive stress hypothesis have important implications for deciphering the pathogenesis of certain diseases in pregnant animals, including humans, which in turn may be applied to preventing and treating their occurrence.

Genome-wide epigenetic signatures of childhood adversity in early life: Opportunities and challenges

Maternal adversity and fetal glucocorticoid exposure has long-term effects on cardiovascular, metabolic and behavioral systems in offspring that can persist throughout the lifespan. These data, along with other environmental exposure data, implicate epigenetic modifications as potential mechanisms for long-term effects of maternal exposures on adverse health outcomes in offspring. Advances in microarray, sequencing and bioinformatic approaches have enabled recent studies to examine the genome-wide epigenetic response to maternal adversity. Studies of maternal exposures to xenobiotics such as arsenic and smoking have been performed at birth to examine fetal epigenomic signatures in cord blood relating to adult health outcomes. However, there have been no epigenomic studies examining these effects in animal models. On the other hand, to date, only a few studies of the effects of maternal psychosocial stress have been performed in human infants, and the majority of animal studies have examined epigenomic outcomes in adulthood. In terms of maternal exposure to excess glucocorticoids by synthetic glucocorticoid treatment, there has been no epigenetic study performed in humans and only a few studies undertaken in animal models. This review emphasizes the importance of examining biomarkers of exposure to adversity throughout development to identify individuals at risk and to target interventions. Thus, research performed at birth will be reviewed. In addition, potential subject characteristics associated with epigenetic modifications, technical considerations, the selection of target tissues and combining human studies with animal models will be discussed in relation to the design of experiments in this field of study.

Excess Hydrocortisone Hampers Placental Nutrient Uptake Disrupting Cellular Metabolism

Low birth weight increases neonatal morbidity and mortality, and surviving infants have increased risk of metabolic and cardiovascular disturbances later in life, as well as other neurological, psychiatric, and immune complications. A gestational excess of glucocorticoids (GCs) is a well-known cause for fetal growth retardation, but the biological basis for this association remains elusive. Placental growth is closely related to fetal growth. The placenta is the main regulator of nutrient transport to the fetus, resulting from the difference between placental nutrient uptake and the placenta's own metabolism. The aim of this study was to analyze how excess hydrocortisone affects placental glucose and lipid metabolism. Human placenta explants from term physiological pregnancies were cultured for 18 hours under different hydrocortisone concentrations (2.75, 5.5, and 55 mM; 1, 2, and 20 mg/ml). Placental glucose and lipid uptake and the metabolic partitioning of fatty acids were quantified by isotopic techniques, and expression of specific glucose transporter GLUT1 was quantified by western blot. Cell viability was assessed by MTT, immunohistochemistry and caspase activity. We found that excess hydrocortisone impairs glucose uptake and lipoprotein lipase (LPL) activity, coincident with a GC-dose dependent inhibition of fatty acid oxidation and esterification. None of the experimental conditions showed an increased cell death. In conclusion, our results show that GC overexposure exerts a dysfunctional effect on lipid transport and metabolism and glucose uptake in human placental explants. These findings could well be directly related to a reduced placental growth and possibly to a reduced supply of nutrients to the fetus and the consequent fetal growth retardation and metabolic programming.

Prenatal Steroids and Metabolic Dysfunction: Lessons from Sheep

Prenatal exposure to excess steroids or steroid mimics can disrupt the normal developmental trajectory of organ systems, culminating in adult disease. The metabolic system is particularly susceptible to the deleterious effects of prenatal steroid excess. Studies in sheep demonstrate that prenatal exposure to excess native steroids or endocrine-disrupting chemicals with steroidogenic activity, such as bisphenol A, results in postnatal development of numerous cardiometabolic perturbations, including insulin resistance, increased adiposity, altered adipocyte size and distribution, and hypertension. The similarities in the phenotypic outcomes programmed by these different prenatal insults suggest that common mechanisms may be involved, and these may include hormonal imbalances (e.g., hyperandrogenism and hyperinsulinemia), oxidative stress, inflammation, lipotoxicity, and epigenetic alterations. Animal models, including the sheep, provide mechanistic insight into the metabolic repercussions associated with prenatal steroid exposure and represent valuable research tools in understanding human health and disease. Focusing on the sheep model, this review summarizes the cardiometabolic perturbations programmed by prenatal exposure to different native steroids and steroid mimics and discusses the potential mechanisms underlying the development of adverse outcomes.

Transplacental versus direct fetal corticosteroid treatment for accelerating fetal lung maturation where there is a risk of preterm birth

BACKGROUND

Despite major advances in medical technology, the incidence of preterm birth remains high. The use of antenatal corticosteroid administered transplacentally, by intramuscular injection to women at risk of preterm birth, has reduced the incidence of respiratory distress syndrome and increased the survival rates of preterm infants. However, this intervention also comes with its own risks and side effects. Animal studies and early studies in pregnant women at risk of preterm birth have reported the use of an alternative route of administration, by direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance, in an attempt to minimise the side-effect profile. Direct fetal corticosteroid administration may have benefits over maternal administration in terms of safety and efficacy.

OBJECTIVES

To assess if different routes of corticosteroid administration (maternal versus direct fetal) have effects on health outcomes for women and their babies.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (25 October 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (25 October 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing maternal with direct fetal routes of antenatal corticosteroid administration in women at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

The two review authors independently assessed study eligibility. In future updates of this review, at least two review authors will extract data and assess the risks of bias in included studies. We will also assess the quality of the evidence using the GRADE approach.

MAIN RESULTS

We did not identify any eligible randomised controlled trials to include in this review.

AUTHORS' CONCLUSIONS

The available clinical studies carried out so far on animals and human have shown that direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance is feasible, but data on health outcomes are lacking. Uncertainty therefore persists as to which method could provide better efficacy and safety. Randomised controlled trials are required focusing on the benefits and harms of transplacental versus direct fetal corticosteroid treatment. Until the uncertainties have been addressed, it is advisable to stay with the current standard of antenatal transplacental maternally-administered corticosteroid treatment.

The role of ACE2, angiotensin-(1-7) and Mas1 receptor axis in glucocorticoid-induced intrauterine growth restriction

BACKGROUND

Plasma and urine levels of the potent vasodilator Ang-(1-7) are elevated in mid and late pregnancy and are correlated with elevated placental angiogenesis, fetal blood flow, and rapid fetal growth. We hypothesized that Ang-(1-7), its receptor (Mas1) and the enzymes involved in Ang-(1-7) production (ACE2 and Membrane metallo-endopeptidase; MME) are down regulated in response to glucocorticoid administration contributing to IUGR.

METHODS

Pregnant female Sprague-Dawley rats were injected with dexamethasone (DEX; 0.4 mg/kg/day) starting from 14 day gestation (dg) till sacrifice at 19 or 21 dg while control groups were injected with saline (n = 6/group). The gene and protein expression of ACE2, MME, Ang-(1-7) and Mas1 receptor in the placental labyrinth (LZ) and basal zones (BZ) were studied.

RESULTS

DEX administration caused a reduction in LZ weight at 19 and 21 dg (p < 0.001). IUGR, as shown by decreased fetal weights, was evident in DEX treated rats at 21 dg (p < 0.01). ACE2 gene expression was elevated in the LZ of control placentas at 21 dg (p < 0.01) compared to 19 dg and DEX prevented this rise at both gene (p < 0.01) and protein levels (p < 0.05). In addition, Ang-(1-7) protein expression in LZ was significantly reduced in DEX treated rats at 21 dg (p < 0.05). On the other hand, Mas1 and MME were upregulated in LZ at 21 dg in both groups (p < 0.05 and p < 0.001, respectively).

CONCLUSION

The results of this study indicate that a reduced expression of ACE2 and Ang-(1-7) in the placenta by DEX treatment may be responsible for IUGR and consequent disease programming later in life.

Pregnancy outcomes following the administration of high doses of dexamethasone in early pregnancy

OBJECTIVE

In the present study, we aimed to evaluate the effects of high doses of dexamethasone (DEX) in early pregnancy on pregnancy outcomes.

METHODS

Pregnant BALB/c mice were treated with high-dose DEX in the experimental group or saline in the control group on gestational days (GDs) 0.5 to 4.5. Pregnant mice were sacrificed on GDs 7.5, 13.5, or 18.5 and their peripheral blood, placentas, fetuses, and uterine tissue were collected. Decidual and placenta cell supernatants were examined to evaluate the effect of DEX on the proliferation of mononuclear cells, the quantity of uterine macrophages and uterine natural killer (uNK) cells, and levels of progesterone and 17β-estradiol, as determined by an 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay, immunohistochemistry, and enzyme-linked immunosorbent assay, respectively. We also were measured fetal and placental growth parameters on GD 18.5.

RESULTS

We found that high doses of DEX were associated with an increased abortion rate, enhancement of the immunosuppressive effect of the decidua, alterations in placental growth parameters, decreased progesterone and 17β-estradiol levels, and a reduced frequency of macrophages and uNK cells.

CONCLUSION

Our data suggest that the high-dose administration of DEX during early pregnancy negatively affected pregnancy outcomes.

Repeat doses of prenatal corticosteroids for women at risk of preterm birth for improving neonatal health outcomes

BACKGROUND

It has been unclear whether repeat dose(s) of prenatal corticosteroids are beneficial.

OBJECTIVES

To assess the effectiveness and safety of repeat dose(s) of prenatal corticosteroids.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (20 January 2015), searched reference lists of retrieved studies and contacted authors for further data.

SELECTION CRITERIA

Randomised controlled trials of women who had already received a single course of corticosteroids seven or more days previously and considered still at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data independently.

MAIN RESULTS

We included 10 trials (a total of 4733 women and 5700 babies) with low to moderate risk of bias. Treatment of women who remain at risk of preterm birth seven or more days after an initial course of prenatal corticosteroids with repeat dose(s), compared with no repeat corticosteroid treatment, reduced the risk of their infants experiencing the primary outcomes respiratory distress syndrome (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.75 to 0.91, eight trials, 3206 infants, number needed to treat to benefit (NNTB) 17, 95% CI 11 to 32) and serious infant outcome (RR 0.84, 95% CI 0.75 to 0.94, seven trials, 5094 infants, NNTB 30, 95% CI 19 to 79).Treatment with repeat dose(s) of corticosteroid was associated with a reduction in mean birthweight (mean difference (MD) -75.79 g, 95% CI -117.63 to -33.96, nine trials, 5626 infants). However, outcomes that adjusted birthweight for gestational age (birthweight Z scores, birthweight multiples of the median and small-for-gestational age) did not differ between treatment groups.At early childhood follow-up, no statistically significant differences were seen for infants exposed to repeat prenatal corticosteroids compared with unexposed infants for the primary outcomes (total deaths; survival free of any disability or major disability; disability; or serious outcome) or in the secondary outcome growth assessments. In women, for the two primary outcomes, there was no increase in infectious morbidity of chorioamnionitis or puerperal sepsis, and the likelihood of a caesarean birth was unchanged.

AUTHORS' CONCLUSIONS

The short-term benefits for babies of less respiratory distress and fewer serious health problems in the first few weeks after birth support the use of repeat dose(s) of prenatal corticosteroids for women still at risk of preterm birth seven days or more after an initial course. These benefits were associated with a small reduction in size at birth. The current available evidence reassuringly shows no significant harm in early childhood, although no benefit.Further research is needed on the long-term benefits and risks for the woman and baby. Individual patient data meta-analysis may clarify how to maximise benefit and minimise harm.

Antenatal glucocorticoids: where are we after forty years?

Since their introduction more than forty years ago, antenatal glucocorticoids have become a cornerstone in the management of preterm birth and have been responsible for substantial reductions in neonatal mortality and morbidity. Clinical trials conducted over the past decade have shown that these benefits may be increased further through administration of repeat doses of antenatal glucocorticoids in women at ongoing risk of preterm and in those undergoing elective cesarean at term. At the same time, a growing body of experimental animal evidence and observational data in humans has linked fetal overexposure to maternal glucocorticoids with increased risk of cardiovascular, metabolic and other disorders in later life. Despite these concerns, and somewhat surprisingly, there has been little evidence to date from randomized trials of longer-term harm from clinical doses of synthetic glucocorticoids. However, with wider clinical application of antenatal glucocorticoid therapy there has been greater need to consider the potential for later adverse effects. This paper reviews current evidence for the short- and long-term health effects of antenatal glucocorticoids and discusses the apparent discrepancy between data from randomized clinical trials and other studies.

Diet reduction to requirements in obese/overfed ewes from early gestation prevents glucose/insulin dysregulation and returns fetal adiposity and organ development to control levels

Obesity at conception and excess gestational weight gain pose significant risks for adverse health consequences in human offspring. This study evaluated the effects of reducing dietary intake of obese/overfed ewes beginning in early gestation on fetal development. Sixty days prior to conception, ewes were assigned to a control diet [CON: 100% of National Research Council (NRC) recommendations], a diet inducing maternal obesity (MO: 150% of NRC recommendations), or a maternal obesity intervention diet (MOI: 150% of NRC recommendations to day 28 of gestation, then 100% NRC) until necropsy at midgestation (day 75) or late (day 135) gestation. Fetal size and weight, as well as fetal organ weights, were greater (P < 0.05) at midgestation in MO ewes than those of CON and MOI ewes. By late gestation, whereas fetal size and weight did not differ among dietary groups, cardiac ventricular weights and wall thicknesses as well as liver and perirenal fat weights remained elevated in fetuses from MO ewes compared with those from CON and MOI ewes. MO ewes and fetuses exhibited elevated (P < 0.05) plasma concentrations of triglycerides, cholesterol, insulin, glucose, and cortisol at midgestation compared with CON and MOI ewes and fetuses. In late gestation, whereas plasma triglycerides and cholesterol, insulin, and cortisol remained elevated in MO vs. CON and MOI ewes and fetuses, glucose concentrations were elevated in both MO and MOI fetuses compared with CON fetuses, which was associated with elevated placental GLUT3 expression in both groups. These data are consistent with the concept that reducing maternal diet of obese/overfed ewes to requirements from early gestation can prevent subsequent alterations in fetal growth, adiposity, and glucose/insulin dynamics.

Elevated glucocorticoids during ovine pregnancy increase appetite and produce glucose dysregulation and adiposity in their granddaughters in response to ad libitum feeding at 1 year of age

OBJECTIVE

Synthetic glucocorticoids (sGCs) are administered to women threatening preterm labor. We have shown multigenerational endocrine and metabolic effects of fetal sGC exposure. We hypothesized that sGC exposure would alter the second filial generation (F2) offspring neonatal leptin peak that controls development of appetitive behavior with metabolic consequences.

STUDY DESIGN

F0 nulliparous ewes were bred to a single ram. Beginning at day 103 of gestation (term 150 days), dexamethasone (DEX) ewes received 4 injections of 2 mg DEX intramuscularly, 12 hours apart. Control ewes received saline. Ewes lambed naturally. At 22 months of age, F1 offspring were mated to produce F2 offspring. At 10 months of age, F2 female offspring were placed on an ad libitum feeding challenge for 12 weeks.

RESULTS

DEX F2 female offspring did not show a postnatal leptin peak and their plasma cortisol concentration was elevated in the first days of life. During the feeding challenge, DEX F2 offspring consumed 10% more feed and gained 20% more weight compared with control F2 offspring. At the end of the feeding challenge, DEX F2 offspring had greater adiposity compared with control F2 offspring. F2 sGC offspring showed impaired insulin secretion in response to an intravenous glucose tolerance test.

CONCLUSION

sGC administration to F0 mothers eliminates the neonatal leptin peak in F2 female offspring potentially by inhibition caused by elevated cortisol in the DEX F2 offspring. F2 offspring showed increased appetite, weight gain, and adiposity during an ad libitum feeding challenge accompanied by decreased insulin response to an intravenous glucose tolerance test.

Combined quantification of corticotropin-releasing hormone, cortisol-to-cortisone ratio and progesterone by liquid chromatography-Tandem mass spectrometry in placental tissue

With mid-gestation the production of placental corticotropin-releasing hormone (CRH) starts to steadily increase. The fetal peptide CRH excerts direct functions at the feto-maternal interface (vasodilatation, timing of birth) via its interaction with progesterone and indirectly ensures maturation and growth of fetal organ systems for delivery by driving fetal cortisol production via its induction of adrenocorticotropic hormone release. This feedback loop is tightly controlled by the amount of enzymatic cortisol/cortisone turnover in the placental syncytiotrophoblast by 11β-hydroxy-steroid dehydrogenase type 2 (11β-HSD2). Traditionally, placental tissue hormones have been quantified by immunological methods (e.g. RIA or ELISA), which have the drawback of possible cross-reactivity and tissue perturbations. Most importantly, it is not possible to quantify CRH and steroid hormones, such as cortisol, cortisone and progesterone together in the same sample with these methods. Hence, we aimed to develop and validate a quantitative mass spectrometry (MS) method for multi-modal quantification of these placental hormones: While CRH was readily detectable throughout the placenta, the placental levels of progesterone and especially cortisol and cortisone were higher at the placental base facing the maternal side. The HPLC-MS/MS procedure showed excellent selectivity and sufficient limit of quantification in placental tissue homogenates to allow for simultaneous detection of CRH, cortisol and cortisone, and progesterone.

Multigenerational effects of fetal dexamethasone exposure on the hypothalamic-pituitary-adrenal axis of first- and second-generation female offspring

OBJECTIVE

Synthetic glucocorticoid (sGC) administration to women threatening preterm delivery increases neonatal survival. Evidence shows that fetal exposure to glucocorticoid levels higher than appropriate for current maturation programs offspring development. We examined fetal sGC multigenerational effects on F1 and F2 female offspring hypothalamo-pituitary-adrenal axis (HPAA) function.

STUDY DESIGN

At 0.7 gestation, pregnant F0 ewes received 4 dexamethasone injections (2 mg, approximately 60 μg/kg(-1) per day(-1), 12 hours apart) or saline (control). F1 female offspring were bred to produce F2 female offspring. Postpubertal HPAA function was tested in F1 and F2 ewes.

RESULTS

F1 and F2 ewe lambs showed reduced birthweight and morphometrics. Dexamethasone increased baseline but reduced stimulated HPAA activity in F1 and F2 female offspring.

CONCLUSION

This is the first demonstration that sGC doses in the clinical range have multigenerational effects on hypothalamo-pituitary-adrenal activity in a precocial species, indicating the need for the study of long-term effects of fetal sGC exposure.

The role of cortisol in chronic binge alcohol-induced cerebellar injury: Ovine model

Women who drink alcohol during pregnancy are at high risk of giving birth to children with neurodevelopmental disorders. Previous reports from our laboratory have shown that third trimester equivalent binge alcohol exposure at a dose of 1.75 g/kg/day results in significant fetal cerebellar Purkinje cell loss in fetal sheep and that both maternal and fetal adrenocorticotropin (ACTH) and cortisol levels are elevated in response to alcohol treatment. In this study, we hypothesized that repeated elevations in cortisol from chronic binge alcohol are responsible at least in part for fetal neuronal deficits. Animals were divided into four treatment groups: normal control, pair-fed saline control, alcohol and cortisol. The magnitude of elevation in cortisol in response to alcohol was mimicked in the cortisol group by infusing pregnant ewes with hydrocortisone for 6 h on each day of the experiment, and administering saline during the first hour in lieu of alcohol. The experiment was conducted on three consecutive days followed by four days without treatment beginning on gestational day (GD) 109 until GD 132. Peak maternal blood alcohol concentration in the alcohol group was 239 ± 7 mg/dl. The fetal brains were collected and processed for stereological cell counting on GD 133. The estimated total number of fetal cerebellar Purkinje cells, the reference volume and the Purkinje cell density were not altered in response to glucocorticoid infusion in the absence of alcohol. These results suggest that glucocorticoids independently during the third trimester equivalent may not produce fetal cerebellar Purkinje cell loss. However, the elevations in cortisol along with other changes induced by alcohol could together lead to brain injury seen in the fetal alcohol spectrum disorders.

Glucocorticoids as mediators of developmental programming effects

Epidemiological evidence suggests that exposure to an adverse environment in early life is associated with an increased risk of cardio-metabolic and behavioral disorders in adulthood, a phenomenon termed 'early life programming'. One major hypothesis for early life programming is fetal glucocorticoid overexposure. In animal studies, prenatal glucocorticoid excess as a consequence of maternal stress or through exogenous administration to the mother or fetus is associated with programming effects on cardiovascular and metabolic systems and on the brain. These effects can be transmitted to subsequent generations. Studies in humans provide some evidence that prenatal glucocorticoid exposure may exert similar programming effects on glucose/insulin homeostasis, blood pressure and neurodevelopment. The mechanisms by which glucocorticoids mediate these effects are unclear but may include a role for epigenetic modifications. This review discusses the evidence for glucocorticoid programming in animal models and in humans.

Growth and insulin dynamics in two generations of female offspring of mothers receiving a single course of synthetic glucocorticoids

OBJECTIVE

Synthetic glucocorticoid administration to women threatening preterm delivery increases neonatal survival. However, mounting evidence shows that fetal exposure to glucocorticoid levels higher than appropriate for current maturation adversely programs offspring development. We examined fetal synthetic glucocorticoid multigenerational metabolic effects on F1 and F2 female offspring.

STUDY DESIGN

At 0.7 gestation, pregnant F0 ewes received 4 injections of dexamethasone (2 mg, approximately 60 ug.kg(-1) day(-1) 12 hours apart) or saline (control). F1 female offspring were bred to produce F2 female offspring. Postpubertal pancreatic β-cell function was tested in F1 and F2 by intravenous glucose tolerance test.

RESULTS

F1 and F2 ewe lambs showed reduced birthweight and morphometrics, and similar increased fasting glucose and decreased intravenous glucose tolerance test β-cell response.

CONCLUSION

This is the first demonstration of multigenerational programming of later life β-cell response by clinically relevant doses of synthetic glucocorticoid indicating the need for study of long-term effects of fetal exposure to synthetic glucocorticoid.

Repeat doses of prenatal corticosteroids for women at risk of preterm birth for improving neonatal health outcomes

BACKGROUND

It has been unclear whether repeat dose(s) of prenatal corticosteroids are beneficial.

OBJECTIVES

To assess the effectiveness and safety of repeat dose(s) of prenatal corticosteroids.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2011), searched reference lists of retrieved studies and contacted authors for further data.

SELECTION CRITERIA

Randomised controlled trials of women who had already received a single course of corticosteroids seven or more days previously and considered still at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data independently.

MAIN RESULTS

We included 10 trials (more than 4730 women and 5650 babies) with low to moderate risk of bias. Treatment of women who remain at risk of preterm birth seven or more days after an initial course of prenatal corticosteroids with repeat dose(s), compared with no repeat corticosteroid treatment, reduced the risk of their infants experiencing the primary outcomes respiratory distress syndrome (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.75 to 0.91, eight trials, 3206 infants, numbers needed to treat (NNT) 17, 95% CI 11 to 32) and serious infant outcome (RR 0.84, 95% CI 0.75 to 0.94, seven trials, 5094 infants, NNT 30, 95% CI 19 to 79).Treatment with repeat dose(s) of corticosteroid was associated with a reduction in mean birthweight (mean difference (MD) -75.79 g, 95% CI -117.63 to -33.96, nine trials, 5626 infants). However, outcomes that adjusted birthweight for gestational age (birthweight Z scores, birthweight multiples of the median and small-for-gestational age) did not differ between treatment groups.At early childhood follow-up no statistically significant differences were seen for infants exposed to repeat prenatal corticosteroids compared with unexposed infants for the primary outcomes (total deaths; survival free of any disability or major disability; disability; or serious outcome) or in the secondary outcome growth assessments.

AUTHORS' CONCLUSIONS

The short-term benefits for babies of less respiratory distress and fewer serious health problems in the first few weeks after birth support the use of repeat dose(s) of prenatal corticosteroids for women still at risk of preterm birth seven days or more after an initial course. These benefits were associated with a small reduction in size at birth. The current available evidence reassuringly shows no significant harm in early childhood, although no benefit.Further research is needed on the long-term benefits and risks for the woman and baby. Individual patient data meta-analysis may clarify how to maximise benefit and minimise harm.    

Antenatal corticosteroids for preterm birth: dose-dependent reduction in birthweight, length and head circumference

AIM

This study was undertaken to evaluate the effects of repeated courses of antenatal corticosteroids (ACS) on foetal growth.

METHODS

We studied 94 infants exposed to 2-9 courses of ACS. Mean gestational age (GA) at first exposure was 29 and at birth 34 weeks. Exposure data were retrieved from case record files. Information on potential confounders was collected from the Swedish Medical Birth Registry. Standard deviation scores (SDS) for birthweight (BW), birthlength (BL) and head circumference (HC) were calculated and considered as outcomes.

RESULTS

GA at start of ACS did not affect outcome. BW-SDS, BL-SDS and HC-SDS were -0.21, -0.19 and +0.25 in infants exposed to two courses, compared to -1.01, -1.04 and -0.23 in infants exposed to ≥ 4 courses of ACS (p = 0.04-0.07). In multiple regression analyses, ≥ 4 courses were associated with lower BW-SDS, BL-SDS and HC-SDS (p = 0.007-0.04) compared to SDS after 2-3 courses. The effects from ≥ 4 courses on BW and BL were comparable to reduction in birth size seen in twins and on HC to that observed after maternal smoking.

CONCLUSIONS

Multiple courses of ACS are associated with a dose-dependent decline in foetal growth, which may affect later development and health.

Physiological changes in maternal cortisol do not alter expression of growth-related genes in the ovine placenta

OBJECTIVES

The aim of this study was to investigate the effect of cortisol on growth-related genes in the ovine placenta.

STUDY DESIGN

Ewes carrying singleton pregnancies were operated on between 112 and 116 days of gestation (115 ± 0.4, term = 147 days) and randomly assigned into three groups: six control animals, five ewes that were administered cortisol by continuous intravenous infusion (1 mg/kg/day, high cortisol), and five ewes that were adrenalectomized and replaced with 0.5-0.6 mg cortisol/kg/day and 3 μg aldosterone/kg/day to produce cortisol concentrations equivalent to pre-pregnancy values (low cortisol). At necropsy (130 ± 0.2 days of gestation), placental tissue was frozen and stored at -80 °C for mRNA analysis.

MAIN OUTCOME MEASURES

To assess potential molecular mechanisms by which cortisol alters placental structure and function and fetal growth.

RESULTS

Cortisol levels did not significantly affect 11β-hydroxysteroid dehydrogenase 1 and 2 enzymes, glucocorticoid receptor, mineralocorticoid receptor and angiotensin II receptor, type 1 (AT1R) expression levels. Gene expression levels of AT2R were increased in the high cortisol group for type B placentomes. There was little effect of cortisol on the insulin-like growth factor (IGF) axis. There was significantly more IGF-I mRNA in B versus A type and more IGFBP-2 mRNA in B and C type versus A type placentomes regardless of treatment (p < 0.05).

CONCLUSIONS

These data suggest that cortisol increases placental AT2R expression at high concentrations whereas it has little effect on the placental IGF axis.

Postnatal ontogeny of the glucocorticoid receptor in the hippocampus

Corticosteroid hormones are important intrinsic factors that not only mediate the response to stress but also largely contribute to the main physiological processes. The biological actions of these steroids involve, first of all, the activation of specific receptors, namely mineralocorticoid (MR) and glucocorticoid (GR) receptors. These two receptor types govern a flexible and well-balanced mechanism that leads to the often opposing changes in the cell. The hippocampus is the central part of the extrahypothalamic feedback loop in the control of the hypothalamic-pituitary-adrenal (HPA) axis activity. The coexpression of both MR and GR in the hippocampus serves a coordinated response to corticosteroids in the hippocampal neurons, thereby mediating the neuronal excitability, stress response, and behavioral adaptation. Each receptor type reveals distinct ontogenetic pattern over the postnatal period. This review addresses the issues relating to postnatal development of the HPA axis and especially the hippocampal expression of the GR proteins in intact and prenatally stressed rats.

Should we be prescribing repeated courses of antenatal corticosteroids?

Single-course treatment with antenatal corticosteroids has been shown to enhance fetal maturation before preterm birth and to improve outcomes for the preterm infant. Based on this success, practitioners expanded use of the treatment to repeated courses of antenatal corticosteroids ahead of evidence demonstrating benefit and excluding harm. Experiments with animals and cohort studies have provided a body of evidence suggesting that repeated doses may further improve lung maturation but may be accompanied by deleterious effects on the developing brain and other organs. Randomised controlled trials of repeated treatments to date have provided mixed evidence but in general may indicate a small benefit in terms of postnatal lung function, but this is accompanied by restricted growth which may include the brain. In view of the well-established role that corticosteroids are known to play in brain development, and the marginal difference that repeated courses may make to outcome in the context of modern neonatal care, antenatal corticosteroid treatments should be restricted to single-course treatment.

Altered placental function of 11beta-hydroxysteroid dehydrogenase 2 knockout mice

Fetal glucocorticoid exposure is a key mechanism proposed to underlie prenatal "programming" of adult cardiometabolic and neuropsychiatric disorders. Regulation of fetal glucocorticoid exposure is achieved by the placental glucocorticoid "barrier," which involves glucocorticoid inactivation within the labyrinth zone of the murine placenta by 11beta-hydroxysteroid dehydrogenase 2 (11beta-HSD2). Thus, the absence of placental 11beta-HSD2 may impact on fetal and placental development. The current study investigated transport of amino acids and glucose, key factors required for fetal growth, and vascular development in placentas from 11beta-HSD2(+/+), (+/-), and (-/-) fetuses derived from 11beta-HSD2(+/-) matings. At embryonic d 15 (E15) (term = E19), 11beta-HSD2(-/-) fetal weight was maintained in comparison to 11beta-HSD2(+/+) fetuses. The maintenance of 11beta-HSD2(-/-) fetal weight occurred despite a reduction in placental weight, suggesting that compensatory changes occur in the placenta to maintain function. However, by E18, 11beta-HSD2(-/-) fetal and placental weights were both reduced. Transport studies revealed up-regulation of placental amino acid transport to 11beta-HSD2(-/-) offspring at E15, coinciding with an increase in the expression of the amino acid transporters. Furthermore, at E18, placental glucose transport to 11beta-HSD2(-/-) offspring was markedly reduced, correlating with lower fetal weight and a decrease in glucose transporter 3 expression. Stereological analyses of the labyrinth zone of the placenta revealed that the reduction in placental weight at E18 was associated with restriction of the normal increase in fetal vessel density over the final third of pregnancy. Our data suggest that restriction of fetal growth in 11beta-HSD2(-/-) mice is mediated, at least in part, via altered placental transport of nutrients and reduction in placental vascularization.

Transgenerational epigenetic effects

Transgenerational epigenetic effects include all processes that have evolved to achieve the nongenetic determination of phenotype. There has been a long-standing interest in this area from evolutionary biologists, who refer to it as non-Mendelian inheritance. Transgenerational epigenetic effects include both the physiological and behavioral (intellectual) transfer of information across generations. Although in most cases the underlying molecular mechanisms are not understood, modifications of the chromosomes that pass to the next generation through gametes are sometimes involved, which is called transgenerational epigenetic inheritance. There is a trend for those outside the field of molecular biology to assume that most cases of transgenerational epigenetic effects are the result of transgenerational epigenetic inheritance, in part because of a misunderstanding of the terms. Unfortunately, this is likely to be far from the truth.

Guideline for the use of antenatal corticosteroids for fetal maturation

The aim is to present a document, which is based on current evidence and serves as a guideline for use in clinical practice. The following questions are addressed: Is the use of antenatal corticosteroids (ACS) an effective therapy? Who are the candidates for antenatal corticosteroid therapy? Is there benefit after 34 weeks' gestation? When is the optimal time to treat? Which are the optimal steroids; what is the ideal dose and route of administration? Are there any contraindications to the administration of ACS? Are antenatal corticosteroids indicated in women with premature rupture of membranes (PROM)? Is the use of ACS recommended in pregnancies complicated by maternal diabetes mellitus? Should the treatment with corticosteroids be repeated?

Diagnosis and management of fetal growth restriction: the role of fetal therapy

Fetal growth restriction remains a major cause of perinatal morbidity and mortality in modern obstetric practice. Placental insufficiency is the most common association, but is often a diagnosis of exclusion. Currently, no treatment can ameliorate or reverse established growth restriction: maximising gestational age and judicious timing of steroid administration and delivery are the primary tasks for the obstetrician. Although comprehensive surveillance of the preterm fetus now includes ductus venosus Doppler studies, its effectiveness in timing delivery has yet to be confirmed in randomised controlled trials. More basic research on the regulation of fetal growth is needed before specific therapies for established growth restriction can be developed.

Maternal and intra-amniotic corticosteroid effects on lung morphometry in preterm lambs

We investigated the effects of intra-amniotic (IA) betamethasone or budesonide injections on lung structure 2 or 7 d after treatment in preterm fetal sheep. Pregnant ewes received intra-amniotic betamethasone (2 mg/kg fetal weight), budesonide (2 mg/kg), saline or maternal intramuscular betamethasone (0.5 mg/kg maternal weight), or saline. Lambs were delivered 2 or 7 d later at 124 d of gestation. Morphometric analysis was conducted on the right upper lung lobe. Intra-amniotic corticosteroids, 2 or 7 d before delivery, resulted in higher average alveolar volumes than controls (2 d: 25%-35%, 7d: 15%-25%). All corticosteroid treatments resulted in thinning of alveolar walls 7 d after treatment and a higher proportion of alveolar ducts and a lower alveolar wall fraction relative to controls 2 or 7 d after treatment. The changes in structural lung indices correlated with the improved lung function at 2 d. Structural lung indices and increased surfactant correlated with the improved lung function at 7 d. Similar structural changes induced by intra-amniotic corticosteroids and maternal intramuscular betamethasone were associated with improvements in lung function at 2 and 7 d.

Antenatal dexamethasone treatment leads to changes in gene expression in a murine late placenta

Antenatal steroids like dexamethasone (DEX) are used to augment fetal lung maturity and there is a major concern that they impair fetal growth. If delivery is delayed after using antenatal DEX, placental function and hence fetal growth may be compromised even further. To investigate the effects of DEX on placental function, we treated 9 pregnant C57/BL6 mice with DEX and 9 pregnant mice were injected with saline to serve as controls. Placental gene expression was studied using microarrays in 3 pairs and other 6 pairs were used to confirm microarray results by semi-quantitative RT-PCR, real-time PCR, in situ hybridization, western blot analysis and Oligo ApopTaq assay. DEX-treated placentas were hydropic, friable, pale, and weighed less (80.0+/-15.1mg compared to 85.6.8+/-7.6mg, p=0.05) (n=62 placentas). Fetal weight was significantly reduced after DEX use (940+/-32mg compared to 1162+/-79mg, p=0.001) (n=62 fetuses). There was >99% similarity within and between the three gene chip data sets. DEX led to down-regulation of 1212 genes and up-regulation of 1382 genes. RT-PCR studies showed that DEX caused a decrease in expression of genes involved in cell division such as cyclins A2, B1, D2, cdk 2, cdk 4 and M-phase protein kinase along with growth-promoting genes such as EGF-R, BMP4 and IGFBP3. Oligo ApopTaq assay and western blot studies showed that DEX-treatment increased apoptosis of trophoblast cells. DEX-treatment led to up-regulation of aquaporin 5 and tryptophan hydroxylase genes as confirmed by real-time PCR, and in situ hybridization studies. Thus antenatal DEX treatment led to a reduction in placental and fetal weight, and this effect was associated with a decreased expression of several growth-promoting genes and increased apoptosis of trophoblast cells.

[Antenatal exposure to corticosteroids for fetal lung maturation and its repercussion on weight, length and head circumference in the newborn infant]

BACKGROUND AND OBJECTIVE

To study the effects of antenatal corticosteroids treatment to promote fetal lung maturation, on fetal growth, depending on the number of the courses administered.

PATIENTS AND METHOD

The study was based on data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), analysing a sample of 29,557 singleton liveborn infants without congenital defects. An stratified analysis by gestational age was performed to compare the weight, length and head circumference at birth, in the exposed and unexposed infants to dexamethasone/betamethasone. To control confounding factors (year of birth, maternal age, gestational age, parity, maternal smoking and/or alcohol consumption, gestational diabetes, non-gestational diabetes and other maternal chronic diseases) we used a general linear model with random effects, being the randomised variable the place of birth.

RESULTS

The exposure to more than one course of antenatal corticosteroids resulted in a significant reduction of birth weight, length and head circumference in singleton preterm infants. The birth weight decreased by 22% (p < 0.0001), the length 5% (p = 0.002) and the head circumference 6% (p = 0.0005). The treatment with only one course reduced also significantly the weight and length but not the head circumference. In addition, we observed a significant interaction between the treatment and gestational age at birth indicating that the effect of corticosteroids is stronger in the most premature babies.

CONCLUSIONS

In this retrospective analysis, the antenatal exposure to corticosteroids to promote fetal maturation is associated with diminished weight, length and head circumference in the premature newborn infant. This negative effect was greater in those premature babies exposed to multiple courses.

Anti-inflammatory interventions in pregnancy: now and the future

A growing body of evidence implicates inflammatory pathways in adverse reproductive outcomes. This expanding evidence suggests that anti-inflammatory interventions may hold promise in reducing the maternal and neonatal morbidities and mortalities associated with these obstetrical complications. Preterm birth, preeclampsia, pregnancy loss and adverse neonatal outcomes have all been associated with the activation of inflammatory pathways during pregnancy. Because of the number of observational human studies, as well as animal models of preterm birth, the mechanisms by which inflammation may promote preterm parturition and adverse effects on the fetus are beginning to be elucidated. Although the future use of anti-inflammatory interventions in this context holds significant promise, much research is still warranted. Only when the pathogenesis of obstetrical complications is more fully understood can meaningful therapeutic interventions become a realistic goal.

Pregnancy effects on distribution of progesterone receptors, oestrogen receptor α, glucocorticoid receptors, Ki-67 antigen and apoptosis in the bovine interplacentomal uterine wall and foetal membranes

Until recently, studies dealing with the uterus of the pregnant cow focus primarily on the placentome or on early and late pregnancy. Thus, there is a paucity of information about many aspects of the interplacentomal uterine wall including adherent foetal membranes. Corresponding tissue specimens were collected at the slaughterhouse and in animals undergoing premature caesarean section. Two specimens per month of pregnancy were assessed immunohistochemically for progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, Ki-67 protein and TUNEL procedure was performed. The latter two methods were employed in three animals each per months 1 and 2, 3 and 4, 7 and 8 and in six animals undergoing caesarean section at days 274 and 275 post insemination or during spontaneous labour. Results indicate that proliferation and apoptosis are of minor importance for tissue homeostasis since both can histochemically be detected only sporadically. Thus, at the sites investigated here, cellular hypertrophy plays an important role for tissue growth during pregnancy. Progesterone receptors, oestrogen receptor alpha and glucocorticoid receptors, however, exhibit cell type and pregnancy stage specific distribution patterns within the tissues assessed. Progesterone receptor immunoreactive scores remained fairly unchanged during pregnancy. Oestrogen receptor alpha scores, however, generally decreased and glucocorticoid receptors increased with ongoing gestation. Progesterone receptors and oestrogen receptor alpha were present in endometrial stroma and in myometrial smooth muscle cells during whole pregnancy. Oestrogen receptor alpha was detectable during whole pregnancy also in uterine glands. Progesterone receptors were, however, present at a very low level at the latter site only during months 1-3 and 6-9. Oestrogen receptor alpha and glucocorticoid receptors may also mediate uterine blood flow since they were present in the tunica media of uterine blood vessels. Results of the present study indicate, that progesterone and its receptor play an important role during whole gestation, mainly for uterine quiescence. Glucocorticoids and their receptors - possibly in cooperation with oestrogens and decreasing amounts of the oestrogen receptor alpha - should trigger processes initiating parturition, such as endometrial prostaglandin production. Further studies - including the periparturient period - should help to understand the exact role of the extraplacental compartment of the uterine wall for the initiation and progress of parturition.

[Preterm corticosteroid therapy and fetal immobility. Case report]

We report a case of fetal immobility following antenatal corticosteroid therapy administered to women in thirty weeks at risk of preterm labor. The short-term side effect of corticosteroid, a decrease in fetal heart rate variation are well known. This case report presents the difficulty of therapy choice in front of fetal immobility and acute fetal distress. We chose a medical supervision. A review of the literature suggests other criteria, such as Doppler of umbilical artery, which could help therapeutical choice.

Administration of prenatal betamethasone suppresses the adrenal-hypophyseal axis in newborns with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a condition that is characterized by pulmonary hypoplasia and pulmonary hypertension. Prenatal betamethasone often is administered to fetuses with CDH to improve pulmonary function. In this study, the authors investigate the possible role of the adrenal-hypophyseal axis in CDH in an animal model and subsequently in human infants with CDH.

METHODS

Twin fetal sheep underwent creation of DH or a sham thoracotomy, and levels of plasma and lung ACTH and plasma cortisol were compared. For the human studies, plasma levels of ACTH, cortisol, and DHEA were measured in cord blood samples collected from 9 CDH (5 that received prenatal betamethasone) and compared with those of 14 normal newborns. In both studies, ACTH and cortisol levels were determined by radioimmunoassay (RIA). Human (DHEA) levels were determined by ELISA.

RESULTS

Plasma ACTH and cortisol levels were elevated in fetal DH sheep compared with sham-operated controls; however, levels of ACTH in lung tissues were not different. Human newborns with CDH who have been exposed to prenatal steroids have significantly lower plasma ACTH, cortisol, and DHEA levels than normal newborns and CDH newborns not exposed to prenatal betamethasone.

CONCLUSIONS

In an ovine model of CDH, the adrenal-hypophyseal axis appears up-regulated in DH fetuses compared with sham-operated animals. Conversely, the adrenal-hypophyseal axis in human CDH newborns appears normal but is suppressed by the administration of prenatal betamethasone.

Cortisol enhances structural maturation of the hypoplastic fetal lung in sheep

Although exogenous corticosteroids advance structural maturation of the fetal lung, they can adversely affect fetal lung and body growth. Our aim was to determine whether cortisol, at physiological doses, can enhance structural maturation of the hypoplastic fetal lung without affecting fetal lung growth. Fetal sheep were divided into four groups (n= 5 for each) and lung hypoplasia (LH) was induced in two groups. Increasing doses of cortisol (1.5-4.0 mg) were infused into one group of fetuses with LH and one group without LH; the other two groups received saline. LH retarded structural development, reduced tropoelastin mRNA levels, reduced hydroxyproline and elastin contents, and increased active matrix metalloproteinase-2 (MMP-2) levels in the fetal lung. Cortisol infusions had no effect on fetal lung growth or body weights. In fetuses with LH, cortisol increased the percentage airspace, reduced the interalveolar wall thickness, increased alveolar number and reduced the increase in active MMP-2 levels. Thus, relatively low doses of cortisol can enhance structural maturation of the fetal lung without adversely affecting fetal lung growth. However, cortisol did not correct the abnormal deposition of elastin within the alveolar parenchyma associated with LH, indicating that secondary septal crest formation remained abnormal.